Normal Results

PT is measured in seconds. Most of the time, results are given as what is called INR (international normalized ratio).

If you are not taking blood thinning medicines, such as warfarin, the normal range for your PT results is:

11 to 13.5 seconds

INR of 0.8 to 1.1

If you are taking warfarin to prevent blood clots, your provider will most likely choose to keep your INR between 2.0 and 3.0.

Ask your provider what result is right for you.

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.

What Abnormal Results Mean

If you are not taking blood thinning medicines, such as warfarin, an INR result above 1.1 means your blood is clotting more slowly than normal. This may be due to:

Bleeding disorders, a group of conditions in which there is a problem with the body's blood clotting process.

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